Voting is already well under way even though Florida doesn't convene its GOP nominating contest until Jan. 31. And both Mitt Romney, coming off of back-to-back victories in Iowa and New Hampshire, and Ron Paul are aggressively reaching out to voters who have requested ballots.

None of their competitors has been nearly as active even though the victor in Florida would get a huge boost of momentum and all of the state's 50 delegates to the national nominating convention.

As of Tuesday, 424,000 Republican absentee ballots had been mailed — to military personnel, overseas residents, and other Floridians — and about 84,000 had been returned in a state that has 4 million registered Republican voters. Early voting in Hillsborough, Hardy, Hendry, Monroe and Collier counties begins Monday and runs through Jan. 29. Florida's other 62 counties will hold early voting Jan. 21-28.

Republican insiders expect as many as a third of the GOP ballots to be cast early in the effort to choose a nominee to oppose President Barack Obama.

"It's pointing towards record turnout," said state GOP spokesman Brian Hughes, adding that the number of Republican absentee ballots requested is more than 200,000 ahead of the 2008 pace at the same point before the election. "We're seeing an enthusiasm not only around being involved in picking our nominee, but beyond that, making sure we beat Obama."

Of all the candidates, Romney had the biggest jump on early voters, who started receiving ballots before he notched his first win at the Jan. 3 Iowa caucuses.

The former Massachusetts governor's campaign is better organized in Florida than any other. And it immediately sent out literature to court voters as soon as ballots were sent in December. That meant some people opened their mailboxes to find both a ballot and an appeal from Romney.

At the same time, an outside group supportive of Romney — the Restore Our Future super PAC — went on the air with TV ads backing him in mid-December, the ads timed to coincide with the delivery of ballots. It has spent more than $750,000 on TV ads.

Romney himself went on the air just after the first of the year. He's spent roughly $800,000 on TV ads so far. No other campaign or candidate-aligned super PAC is on the air.

"Even as Iowa was beginning to heat up, we were already messaging absentee voters in Florida," said Brett Doster, a Tallahassee-based Romney aide. "There were already votes being cast and I can assure you that they got Romney messaging and it looks like they weren't getting any messaging from anyone else."

That was true until Texas Rep. Ron Paul's campaign recently got in the game and sent out its own literature. Former House Speaker Newt Gingrich's campaign planned to start doing the same this week, adding to efforts by its volunteers — and automated calls — to encourage early voting.

Texas Gov. Rick Perry's campaign also has asked volunteers to make calls and has paid for automated calls. Former Utah Gov. Jon Huntsman and former Pennsylvania Sen. Santorum have done little to woo early voters.

Elizabeth Pike, a 71-year-old retiree from Pompano Beach, is among those who already have voted. She cast her absentee ballot for Gingrich — but not because she was courted by the campaign.

"He was speaker of the House. When he wanted to get something through, he was very successful," said Pike. "He can speak well and he could represent us well."

In 2008, about 554,000 absentee ballots were cast overall among nearly 1.2 million early votes cast, but the number of Democratic ballots requested this year is far lower, since Obama doesn't have a primary challenger.

This year, the ballots aren't being returned nearly as quickly as they're going out.

Orange County elections supervisor Bill Cowles said he thinks many voters have been waiting to see what happens in other early states before making up their minds.

Part of that may be to make sure their preferred candidate doesn't drop out before Florida votes.

Seminole County elections supervisor Michael Ertel said he remembers receiving a lot of calls when Republican Fred Thompson dropped out of the 2008 race a week before Florida voted. They wanted to know if they could have their ballot back and vote again. They were out of luck.